Studies Of Sulfate Ion Microfitered Through Ceramic Membrane From Potassium Nitrate Feed Solution

Barium sulfate precipitation has a great influence on the industrial production of potassium nitrate,which result in potassium nitrate low crystallinity,clogging pipes and the cooling crystallization effected,after the adoption of ceramic membrane microfiltration process,both to improve the purity of potassium nitrate and can reduce enterprise cost.Microfiltration process of solvent potassium nitrate production process of sulfur ion impurities was studied by using ceramic membranes with pore diameter of 0.5 and 0.8 ?m.The effects of operating time,trans-membrane pressure,cross-flow velocity,temperature and volume concentration factor on permeate flux.The results show that,with increasing operating time,permeate fluxes decrease rapidly to a steady value. Steady-state fluxes enhance with increasing trans-membrane pressure or cross-flow velocity,and then do not change any more.Steady-state fluxes enhance with increasing temperature.Optimum operating parameters for the 0.8 ?m membrane are trans-membrane pressure 0.12 MPa,cross-flow velocity 3.0 m/s and temperature 30?.Optimum operating parameters for the 0.5 ?m membrane are trans-membrane pressure 0.14 MPa,cross-flow velocity 3.4 m/s and temperature 30?.In the process of concentration, permeate fluxes decrease to a steady value and then decreases rapidly, and the rejections are about 99%.The backflushing can increase efficiently permeate flux,it is possible to recover over 94% of the original flux by a program of backflushing;In addition, the modified completely blocked model can describe the microfiltration processes.Microfiltration process of electroplating wastewater containing sulfate ion for industrial application was also investigated.It found that membrane pore size of 0.8 ?m and the membrane total area of 1.92 m2 can satisfy with the output of 500 ton electroplating wastewater containing sulfate ions per year.